Process of refining mineral oil



Patented Apr. 6, 1937 PATENT OFFICE PROCESS OF REFINING MINERAL OIL William Hunter Volck, Watsonville, Calif., assignor to California Spray-Chemical Corporation, Berkeley, Calif., a corporation of California No Drawing. Application June 13, 1933, Serial No. 675,580

8 Claims.

This invention relates to a process of refining mineral or petroleum oil. It relates more particularly to refinement of petroleum oils or petroleum oil distillates by the action of a selective solvent which will exert a differential solvent action on saturated and unsaturated compounds in the oils and permit separation of the oil into portions, one of which will contain a greatly decreased percentage of unsaturated compounds or a greatly increased percentage of saturated compounds, while the other portion contains a larger percentage of unsaturated compounds.

This invention also relates to a process for producing phytonomic oils which has peculiar advantages over other processes and products now known and in commercial use:

First. The combination of solvents herein disclosed first removes those unsaturated constituents of the oils which are most phytocidal, so

that even though there may remain a substantial percentage of unsaturates, these are not greatly objectionable. This is shown by the difference in absorption of unsaturated constituents in fullers earth. If an oil refined by my process and an oil refined with sulphuric acid each containing the same actual percentage of unsaturated compounds are mixed with fullers earth, the first oil will scarcely darken the fullers earth, while the second will render it quite black if more than a few per cent of unsaturated constituents are present.

Second.The combination of solvents of my process removes more of the light and volatile constituents of the oil stock than it does of the heavy and non-volatile constituents. Thus the more desirable heavy phytonomic oils are conveniently separated from the lighter and less desirable ones by my process.

It has been known for a long time that unsaturated compounds in petroleum oil are deleterious not only because they impart objectionable properties to the oil, .but also because they impart undesirable color and odor to it. Many attempts have been made to improve such oils by removing these unsaturated bodies. One of the best known ways has been to treat the oils with concentrated sulphuric acid or oleum and separate the unsaturated bodies, which become sulphonated, by permitting the sludge to settle and drawing it oil. These and other attempts to refine mineral oils have not been entirely satisfactory partly because of loss of oil and partly because of the cost of the reagents used, and toxicity of some of them.

By the present invention crude petroleum oils or distillates of the same, either before or after treatment with sulphuric acid, are treated with a solvent that will enable unsaturated compounds to be removed from the oil. In carrying out this invention a mixture of acetone and triethanolamine is used as the selective solvent. The triethanolamine used may be the commercial product that contains some monoand diethanolamine.

The mixture of acetone and triethanolamine is introduced into the oil while the oil is being vigorously agitated. The agitation may be continued from about thirty seconds to three or four minutes and the contents of the vessel are then permitted to separate into two layers. The amount of the acetone-triethanolamine mixture that is used may vary from an amount somewhat less than the volume of the oil to three or four times its volume, depending upon the particular oil to be treated. The proportion of acetone to triethanolamine in the solvent mixture may vary from about 98 parts of acetone by volume to 2 parts of triethanolamine up to about 80 parts of acetone to 20 parts of triethanolamine. The agitation and separation may be carried out either at ordinary atmospheric temperatures or the temperature may be increased or de. creased. v

While it is most convenient to operate at ordinary temperatures, the greatly reduced proportion of solvent to oil required at higher temperatures appears to make a temperature of about 50 C, most economical in practice, although temperatures up to C. or higher may be employed.

The amount of oil in the two respective layers, after settling takes place following the acetonetriethanolamine treatment, varies with the character of the oil treated, the amount of acetonetriethanolamine solvent used, and the proportion of acetone to triethanolamine. It is usually desirable to have the solvent or mixture of higher specific gravity than that of the oil. In such instances the upper layer contains oil that has a decreased percentage of unsaturated compounds therein and the lower layer contains oil with an increased percentage of unsaturated compounds therein. The layers are separated in any convenient way and the acetone may be removed from each layer by distillation and recovered. The acetone readily distills off without an appreciable loss of oil. The triethanolamine and its salts precipitate from the oil almost completely after the acetone has been removed. The triethanolamine may be used repeatedly as it does not become greatly deteriorated by using it for a single treatment of the oil. It may be purified in any of the well known ways after it has been used for several treatments.

Each of the two fractions of oil obtained from the first treatment is usually lighter in color than the original oil, due to the fact that some of the coloring matter was removed by triethanolamine. These oil fractions may be filtered to remove more of the coloring materials. Each fraction may be treated again with the acetone and triethanolamine mixture. The more highly purified first fraction yields two fractions, one of which is still more highly purified from unsaturated compounds and the other one is less purified. The more impure of the first yields two fractions, one of which is partially purified and the other one contains even a higher percentage of unsaturated products. This procedure may be continued, using blended fractions having approximately the same percentage of unsaturated compounds therein, although a single purification is often all that is required in order to obtain a sufiiciently purified fraction of the original oil.

The refined or purified mineral oil obtained by this process is well adapted for use as spray oils for protecting plant life from the action of parasites, such as insects, fungus growths, etc., as the oil has parasiticidal properties and is free from deleterious phytocidal impurities. Such purified oils have been found to possess desirable characteristics such as some of those set forth in my prior Patent #1,707,468.

The following specific examples are given as illustrative of the invention. It is to be understood that the invention is not restricted to the particular oils, proportions, times, temperatures, etc.:

Example I 400 volumes of petroleum oil distillate containing 26% of unsaturated compounds were agitated for thirty seconds at 20 C. with 2000 volumes of a mixture of acetone and triethanolamine in the proportion of eighty parts of acetone by volume to twenty parts of triethanolamine and the contents were permitted to settle for about three hours. After separating the two layers and re-- moving the acetone and triethanolamine 290 volumes of oil containing 8% of unsaturated compounds were obtained from one layer and 100 volumes of oil containing of unsaturated compounds were obtained from the other layer. This example was carried out in five treatments using about equal volumes of solvent and oil in each treatment.

Example II 200 volumes of petroleum oil containing 29% of unsaturated compounds were treated with 300 volumes of a mixture of parts of acetone to 5 parts of triethanolamine by agitation for 30 seconds at a temperature of 18 C. and the contents of the vessel were permitted to settle for about 30 minutes. After the removal of the acetone and triethanolamine a fraction of 144 volumes of oil containing 80% of saturated compounds and another fraction of 55 volumes of oil containing 50% of saturated compounds were obtained. This example was carried out in one operation.

I claim:

1. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine as a selective solvent whereby said oil is separated into layers richer respectively in saturated and unsaturated hydrocarbons.

2. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine in the proportion of about two to twenty-five parts of triethanolamine to one hundred parts of acetone by volume as a selective solvent whereby said oil is separated into layers richer respectively in saturated and unsaturated hydrocarbons.

3. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine, the acetone-triethanolamine mixture being about one time to five times the oil by volume as a selective solvent whereby said oil is separated into layers richer respectively in saturated and unsaturated hydrocarbons.

4. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine at a temperature between about 20 C. and 75 C. as a selective solvent whereby said oil is separated into layers richer respectively in saturated and unsaturated hydrocarbons.

5. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine as a selective solvent, permitting it to separate into layers and removing acetone and triethanolamine from one of said layers.

6. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine as a selective solvent, permitting it to separate into layers, removing acetone and triethanolamine from one of said layers, and filtering said layer.

7. The process of refining petroleum oil, which comprises treating said oil with a mixture of acetone and triethanolamine as a selective solvent, permitting it to separate into layers and removing acetone and triethanolamine from the oil of one of said layers and treating it with a mixture of acetone and triethanolamine.

8. The process of refining petroleum oil, which comprises agitating said oil with a mixture of acetone and triethanolamine as a selective solvent for about thirty seconds.

WILLIAM HUNTER VOLCK. 

